Anti-bit balling drilling fluids, and methods of making and use thereof

ABSTRACT

Anti-bit balling drilling fluids and methods of making and using drilling fluids are provided. The anti-bit balling drilling fluid contains water, a clay-based component, and a polyethylene glycol having the formula: H—(O—CH2—CH2)n—OH, where n is an integer from 1 to 50.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Non-Provisional patentapplication Ser. No. 15/485,479 filed Apr. 12, 2017 which claims U.S.Provisional Patent Application Ser. No. 62/454,189 filed Feb. 3, 2017and U.S. Provisional Patent Application Ser. No. 62/454,192 filed Feb.3, 2017, both of which are incorporated by reference herein in theirentirety.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to anti-bitballing drilling fluids and methods of making and using these fluids.Specifically, embodiments of the present disclosure relate to anti-bitballing fluids containing a surfactant or a polyethylene glycol,drilling fluids containing a surfactant or a polyethylene glycol, andmethods of making and using these fluids to control bit ballingtendencies.

BACKGROUND

In the oil drilling industry, bit balling refers to a buildup ofcuttings from clay (also known as shale) that may adhere to a drill bit.Drill “cuttings” are broken bits of solid materials produced as rock orsoil is broken apart that must be continuously removed from the boreholeduring drilling. Bit balling may occur at almost any time, and mayresult in a reduction in the rate of penetration, reduced surface torqueof the drill bit, and an increase in stand pipe pressure. As clayaccumulates and bit balling increases, drilling will slow and,eventually, may have to be stopped for the drill bit to be cleaned.

Conventional additives or coatings may be used to control bit ballingtendencies; however, most additives require an oil phase in the drillingfluid or require an emulsified drilling fluid to be effective. The oilphase in the fluid may provide lubrication necessary for the additivesto function. Some anti-bit balling additives also require a particularpH range and cloud point range to be compatible with the drilling fluidsused. Additionally, the efficacy of conventional additives and coatingsis lacking, often requiring the drill to be frequently removed andcleaned before drilling can proceed.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of specific embodiments of thepresent disclosure can be best understood when read in conjunction withthe following drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1A is a photograph of the accretion tube results for a prior artcomparative example;

FIG. 1B is a photograph of the accretion tube results of another priorart comparative example;

FIG. 2A is a photograph of the accretion tube results of an exampleaccording to the anti-bit balling drilling fluid formulations shown anddescribed in this disclosure; and

FIG. 2B is a photograph of the accretion tube results of another exampleaccording to the anti-bit balling drilling fluid formulations shown anddescribed in this disclosure.

SUMMARY

Accordingly, an ongoing need exists for anti-bit balling drilling fluidsthat effectively reduce and prevent bit balling without requiringdrilling fluid containing an oil phase or emulsified drilling fluid. Thepresent embodiments provide anti-bit balling drilling fluids and methodsof making and using these fluids that address these concerns.

In some embodiments, anti-bit balling drilling fluids are provided thatcontain water, a clay-based component, a surfactant having the formula:R—(OC₂H₄)_(x)—OH, where R is a hydrocarbyl group having from 10 to 20carbon atoms and x is an integer from 1 and 10, or a polyethylene glycolhaving the formula: H—(O—CH₂—CH₂)_(n)—OH, where n is an integer from 1to 50. In some embodiments, the surfactant may have an HLB of from 8 to16.

In further embodiments, methods of producing a drilling fluid areprovided. The methods include mixing water, a clay-based component, asurfactant having the formula: R—(OC₂H₄)_(x)—OH, where R is ahydrocarbyl group having from 10 to 20 carbon atoms and x is an integerfrom 1 and 10, or a polyethylene glycol having the formula:H—(O—CH₂—CH₂)_(n)—OH, where n is an integer from 1 to 50 to produce adrilling fluid.

In still further embodiments, methods of using a drilling fluid indrilling operations are provided. The methods include mixing water, aclay-based component, a surfactant having the formula: R—(OC₂H₄)_(x)—OH,where R is a hydrocarbyl group having from 10 to 20 carbon atoms and xis an integer from 1 and 10, or a polyethylene glycol having theformula: H—(O—CH₂—CH₂)_(n)—OH, where n is an integer from 1 to 50 toproduce a drilling fluid, and introducing the drilling fluid to asubterranean formation.

Additional features and advantages of the described embodiments will beset forth in the detailed description which follows, and in part will bereadily apparent to those skilled in the art from that description orrecognized by practicing the described embodiments, including thedetailed description which follows as well as the claims.

DETAILED DESCRIPTION

Embodiments of the present disclosure are directed to anti-bit ballingdrilling fluids containing water, a clay-based component, and at leastone of either a surfactant having Formula (I):

R—(OC₂H₄)_(x)—OH  Formula (I)

where R is a hydrocarbyl group with 10 to 20 carbons and x is an integerfrom 1 and 10, or a polyethylene glycol having Formula (II):

where n is an integer from 1 to 50.

As a non-limiting example, the anti-bit balling drilling fluids of thepresent disclosure may be used in the oil and gas drilling industries,such as for drilling in oil and gas wells. Oil and gas wells may beformed in subterranean portions of the Earth, sometimes referred to assubterranean geological formations. The wellbore may serve to connectnatural resources, such as petrochemical products, to a ground levelsurface. In some embodiments, a wellbore may be formed in the geologicalformation, for instance, by a drilling procedure. To drill asubterranean well or wellbore, a drill string including a drill bit anddrill collars to weight the drill bit is inserted into a predrilled holeand rotated to cut into the rock at the bottom of the hole, producingrock cuttings. Commonly, the drilling fluid, known as “drilling mud,”may be utilized during the drilling process. To remove the rock cuttingsfrom the bottom of the wellbore, drilling fluid is pumped down throughthe drill string to the drill bit. The drilling fluid may cool andlubricate the drill bit and may provide hydrostatic pressure in thewellbore to provide support to the sidewalls of the wellbore and preventthe sidewalls from collapsing and caving in on the drill string and toprevent fluids in the downhole formations from flowing into the wellboreduring drilling operations. The drilling fluid may also lift the rockcuttings away from the drill bit and upwards as the drilling fluid isrecirculated back to the surface. The drilling fluid may transport rockcuttings from the drill bit to the surface, which can be referred to as“cleaning” the wellbore.

The rock or drill “cuttings” are broken bits of solid materials producedas rock or soil is broken apart that must be continuously removed fromthe borehole during drilling. The cuttings may vary based on thedrilling application, and in some instances may include clay (shale),rock, or soil pieces. These pieces often begin to agglomerate, forming adense slurry that may build up on the drill bit. The increasing use ofwater-based drilling fluids aggravates bit balling problems, as waterfrom the drilling fluid may be absorbed by the cuttings, exacerbatingtheir tendency to stick to the drill bit. Clay cuttings may beparticularly susceptible to cause bit balling problems due to theplastic limit, or water content, of clay.

Clay may be classified based on the Attenberg limits, whichdifferentiate three phases of clay based on water content: the liquidlimit, plastic limit, and plastic index. The liquid limit is thethreshold moisture content at which the clay is so saturated withmoisture that it begins to wash away in an almost-liquid form. Clay atits liquid limit is a muddy liquid that is easily washed from a drillbit. The plastic index of clay refers to the lowest moisture content atwhich the clay may be rolled into threads one eighth of an inch indiameter without breaking into pieces. This clay does not contain muchmoisture and is in an almost-solid form. Clay at its plastic index iseasily brushed away from the drill bit as chalky residue, and is alsonot generally problematic. Finally, the plastic limit of clay refers tothe state between the liquid limit and the plastic index, in which theclay contains enough water to impart stickiness to the clay withoutadding so much water that the clay forms a liquid. This plastic limitmay also be referred to as the “danger zone” of the clay due to theproblems caused by the thick nature and sticky texture of the clay. Clayat the plastic limit is often a viscous, gummy slurry that is verydifficult to manipulate.

Embodiments of the present disclosure relate to anti-bit ballingdrilling fluids containing at least one surfactant or a polyethyleneglycol that may reduce the tendency of bit balling by preventing andreducing the accumulation of cuttings and the adhesion of the cuttingsto a drill bit. According to some embodiments, the surfactant may havethe chemical structure of Formula (I):

R—(OC₂H₄)_(x)—OH  Formula (I)

In Formula (I), R is a hydrocarbyl group having from 10 to 20 carbonatoms and x is an integer from 1 to 10. As used in this disclosure, a“hydrocarbyl group” refers to a chemical group consisting of carbon andhydrogen. Typically, a hydrocarbyl group may be analogous to ahydrocarbon molecule with a single missing hydrogen (where thehydrocarbyl group is connected to another chemical group). Thehydrocarbyl group may contain saturated or unsaturated carbon atoms inany arrangement, including straight (linear), branched, or combinationsof any of these configurations. The hydrocarbyl R group in someembodiments may be an alkyl (—CH₃), alkenyl (—CH═CH₂), or alkynyl (—CCH)group.

In some embodiments, R may have from 10 to 20 carbons, such as from 10to 18 carbons, from 10 to 16 carbons, from 10 to 14 carbons, from 10 to12 carbons, or from 12 to 20 carbons, or from 12 to 15 carbons, or from14 to 20 carbons, or from 16 to 20 carbons, or from 18 to 20 carbons, orfrom 12 to 16 carbons, or from 12 to 15, or from 12 to 14 carbons. Insome embodiments, R may have 12 carbons, or 13 carbons, or 14 carbons or15 carbons. In some particular embodiments, R may have 13 carbons, and,in some embodiments, R may be C₁₃H₂₇ (isotridecyl) or may contain anisotridecyl group.

In Formula (I), x is an integer between 1 and 10. In some embodiments, xmay be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In some embodiments, x may bean integer from 5 to 10, from 5 and 9, from 7 to 10, or from 7 to 9. Insome embodiments, x may be an integer greater than or equal to 5, suchas an integer greater than or equal to 7, or greater than or equal to 8.

The surfactant may be amphiphilic, meaning that it has a hydrophobictail (the non-polar R group) and a hydrophilic head (the polar —OHgroups from ethylene oxide and the alcohol group) that may lower thesurface tension between two liquids or between a liquid. In someembodiments, the surfactant may have a hydrophilic-lipophilic balance(HLB) of from 8 to 16. Without being bound by any particular theory, theHLB of the compound is the measure of the degree to which it ishydrophilic or lipophilic, which may be determined by calculating valuesfor the regions of the molecules in accordance with the Griffin Methodin accordance with Equation 1:

$\begin{matrix}{{HLB} = {20 \times \frac{M_{h}}{M}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

In Equation 1, M_(h) is the molecular mass of the hydrophilic portion ofthe molecule and M is the molecular mass of the entire molecule. Theresulting HLB value gives a result on a scale of from 0 to 20 in which avalue of 0 indicates to a completely hydrophobic/lipophilic molecule anda value of 20 corresponds to a completely hydrophilic/lipophobicmolecule. Generally, a molecule having an HLB of less than 10 islipid-soluble (and thus water-insoluble) and a molecule having an HLB ofgreater than 10 is water-soluble (and thus lipid-insoluble).

In some embodiments, the surfactant may have an HLB of from 8 to 16,such as from 10 to 16, or from 12 to 16, or from 13 to 16, or from 14 to16. In some embodiments, the surfactant may have an HLB of from 15 to16, or from 12 to 15, or from 13 to 15, or from 14 to 15. The surfactantmay have an HLB of from 11 to 12, or 12 to 13, or 13 to 14, or 14 to 15,or 15 to 16. The HLB value may indicate that the surfactant has bothhydrophilic and lipophilic affinities (as the surfactant is amphiphilic)but has a slightly greater tendency towards beinghydrophilic/lipophobic, and thus, may be at least partiallywater-soluble. An HLB value of from 13 to 15 may indicate that thesurfactant is able to act as a detergent. Without being bound by anyparticular theory, the surfactant may aid in dispersing the balled shalecuttings produced by the drill. The HLB of the surfactant may allow themolecule to function as a detergent, producing a dispersing affect andreducing the ability of the shale cuttings to adhere to the bit surface.

The surfactant may be a reaction product of a fatty alcohol ethoxylatedwith ethylene oxide. As used throughout the disclosure, a fatty alcoholrefers to a compound having a hydroxyl (—OH) group and at least onealkyl chain (—R) group. The ethoxylated alcohol compound may be made byreacting a fatty alcohol with ethylene oxide. The ethoxylation reactionin some embodiments may be conducted at an elevated temperature and inthe presence of an anionic catalyst, such as potassium hydroxide (KOH),for example. The ethoxylation reaction may proceed according to Equation2:

The fatty alcohols used as the reactant in Equation 2 to make theethoxylated alcohol compound could include any alcohols having formulaR—OH, where R is a saturated or unsaturated, linear, or branchedhydrocarbyl group having from 10 to 20 carbon atoms, from 10 to 16carbon atoms, or from 12 to 14 carbon atoms. In some embodiments, R maybe a saturated linear hydrocarbyl group. Alternatively, the fattyalcohol may include R that is a branched hydrocarbyl group.

In some embodiments, the R—OH group of the surfactant may be anaturally-derived or synthetically-derived fatty alcohol. Non-limitingexamples of suitable fatty alcohols may include, but are not limited tocapryl alcohol, perlargonic alcohol, decanol (decyl alcohol), undecanol,dodecanol (lauryl alcohol), tridecanol (tridecyl alcohol), myristylalcohol (1-tetradecanol), pentadecanol (pentadecyl alcohol), cetylalcohol, palmitoleyl alcohol, heptadecanol (heptadecyl alcohol) stearylalcohol, nonadecyl alcohol, arachidyl alcohol, other naturally-occurringfatty alcohols, other synthetic fatty alcohols, or combinations of anyof these. In some embodiments, the fatty alcohol may be decanol (decylalcohol) or tridecanol (tridecyl alcohol).

The fatty alcohol may be a naturally occurring fatty alcohol, such as afatty alcohol obtained from natural sources, such as animal fats orvegetable oils, like coconut oil. The fatty alcohol may be ahydrogenated naturally-occurring unsaturated fatty alcohol.Alternatively, the fatty alcohol may be a synthetic fatty alcohol, suchas those obtained from a petroleum source through one or more synthesisreactions. For example, the fatty alcohol may be produced through theoligomerization of ethylene derived from a petroleum source or throughthe hydroformylation of alkenes followed by hydrogenation of thehydroformylation reaction product.

As shown in Equation 2, the reaction product may have the generalchemical formula R—(OCH₂CH₂)_(x)—OH, where R is a saturated orunsaturated, linear or branched hydrocarbyl group having from 5 to 20carbon atoms. According to some embodiments, the R group may be aniso-tridecyl group (—C₁₃H₂₇), as depicted in Chemical Structure A. Itshould be understood that Chemical Structure A depicts one possibleembodiment of the surfactant of Formula (I) in which the R group is aniso-tridecyl group, which is used as a non-limiting example. In someembodiments, Chemical Structure (A) may have 8 ethoxy groups (that is, xequals 8 in Chemical Structure (A)) such that the surfactant is atridecyl alcohol ethyoxylate with an 8:1 molar ratio of ethylene oxidecondensate to branched isotridecyl alcohol having the chemical formulaC₁₃H₂₇—(OCH₂CH₂)₈—OH.

Generally, an x:1 molar ratio of the fatty alcohol to the ethylene oxidemay be utilized to control the level of ethoxylation in Equation 2. Insome embodiments, x may be from 1 to 10, such as 1, 2, 3, 4, 5, 6, 7, 8,9, or 10. In some embodiments, the surfactant may be the reactionproduct of fatty alcohol ethoxylated with ethylene oxide at an 8:1 molarratio of fatty alcohol to ethylene oxide. In some particularembodiments, the surfactant may be a synthetic alcohol oxylate and maybe an ethylene oxide condensate of isotridecyl alcohol. The surfactantmay be produced by an 8:1 molar ratio of ethylene oxide to isotridecylalcohol. In some particular embodiments, the surfactant may be producedby an 8:1 molar ratio of ethylene oxide condensate to synthetic branchedisotridecyl alcohol.

The anti-bit balling drilling fluid may alternatively or additionallycontain a polyethylene glycol having Formula (II):

In Formula (II), n is an integer from 1 to 50. In some embodiments, nmay be varied to achieve the desired molecular weight of thepolyethylene glycol produced. In some embodiments, n may be from 1 to35, or from 1 to 20, or from 1 to 10, or from 10 to 50, or from 25 to50. The polyethylene glycol may have a weight average molecular weightof from 200 grams per mol (g/mol) to 1500 g/mol, as measured accordingto gel permeation chromatography (GPC). In some embodiments, thepolyethylene glycol may have a weight average molecular weight of from200 to 1000 g/mol, or 200 to 500 g/mol, or 250 to 500 g/mol, or 300 to450 g/mol, or 250 to 450 g/mol, or 350 to 450 g/mol. In someembodiments, the polyethylene glycol may have a weight average molecularweight of from 180 to 220 g/mol, or 280 to 320 g/mol, or 380 to 420g/mol, or 580 to 620 g/mol, or 1180 to 1220 g/mol, or 1480 to 1520g/mol. In some embodiments, the polyethylene glycol may have a weightaverage molecular weight of 200 g/mol, or 300 g/mol, or 400 g/mol, or600 g/mol, or 1200 g/mol, or 1500 g/mol.

Without being bound by any particular theory, the molecular weight ofthe polyethylene glycol may help to provide lubrication to the drill bitsurface. The polyethylene glycol may lubricate the drill bit withoutrequiring use of an oil phase in the drilling fluid or use of anemulsified drilling fluid. The adhesion of clay to the drill bit may becaused, at least in part, by electro-chemical attraction of both theclay to the metal drill bit and, as the clay accumulates, clay to clayinteractions. Moreover, the surface of the metal bit may be water-wet,and clay has molecular layers of water adsorbed on its surface. It isbelieved that the clay may adhere to bits and drill collars when forcedinto intimate contact by the force and weight of the drill string due towater molecules between the drill bit and the clay forming hydrogenbonds. The polyethylene glycol and the surfactant both act to reduce thesurface tension, decreasing the accretion of cuttings to the bitsurface. Furthermore, the polyethylene glycol is non-polar and mayeliminate the polarity of the hydrogen bonding, reducing the adhesion ofthe clay to the bit surface.

In some embodiments, the drilling fluid may contain from 0.1 wt % to 10wt % of the surfactant, the polyethylene glycol, or both based on thetotal weight of the drilling fluid. The drilling fluid may contain from0.01 wt % to 20 wt % of the surfactant based on the total weight of thedrilling fluid. The drilling fluid may contain from 0.02 lb/bbl to 180lb/bbl of the surfactant based on the total weight of the drillingfluid, such as from 0.02 to 150 lb/bbl, or from 0.05 to 150 lb/bbl. Insome embodiments, the drilling fluid may contain from 0.1 to 150 lb/bbl,or from 0.1 to 100 lb/bbl, or from 1 to 100 lb/bbl of the surfactant.

Likewise, the drilling fluid may contain may contain from 0.02 lb/bbl to180 lb/bbl of the polyethylene glycol based on the total weight of thedrilling fluid, such as from 0.02 to 150 lb/bbl, or from 0.05 to 150lb/bbl. In some embodiments, the drilling fluid may contain from 0.1 to150 lb/bbl, or from 0.1 to 100 lb/bbl, or from 1 to 100 lb/bbl of thepolyethylene glycol.

In some embodiments, the drilling fluid may contain from 0.1 wt % to 10wt %, or from 1 wt % to 10 wt % of the combined total of the surfactantand the polyethylene glycol. The drilling fluid may contain may containfrom 0.02 lb/bbl to 180 lb/bbl of the surfactant and the polyethyleneglycol based on the total weight of the drilling fluid, such as from0.02 to 150 lb/bbl, or from 0.05 to 150 lb/bbl. In some embodiments, thedrilling fluid may contain from 0.1 to 150 lb/bbl, or from 0.1 to 100lb/bbl, or from 1 to 100 lb/bbl of the surfactant and the polyethyleneglycol.

The clay-based component of the drilling fluid may be any clay-basedmaterial or mud suitable for use in drilling fluids, which may varybased on the application of use. In some embodiments, the clay-basedcomponent may contain, for instance, lime (CaO), CaCO₃, bentonite,montmorillonite clay, barium sulfate (barite), hematite (Fe₂O₃), mullite(3Al₂O₃.2SiO₂ or 2Al₂O₃.SiO₂), kaolin, (Al₂Si₂O₅(OH)₄ or kaolinite),alumina (Al₂O₃, or aluminum oxide), silicon carbide, tungsten carbide,and combinations thereof. In some embodiments, the clay-based componentmay be bentonite. Without being bound by any particular theory, use of aclay-based component may increase the viscosity and rheology of thedrilling fluid to allow for better drill lubrication, shear strength,and transportation of cuttings.

The drilling fluid may contain from 0.01 wt % to 80 wt % of theclay-based component based on the total weight of the drilling fluid.The drilling fluid may contain from 28 to 720 lb/bbl of the clay-basedcomponent based on the total weight of the drilling fluid. In someembodiments, the drilling fluid may contain from 28 to 700 lb/bbl, or 50to 700 lb/bbl, or 100 to 700 lb/bbl, or 200 to 500 lb/bbl of theclay-based component.

The drilling fluid may include water along with the clay-based material.The water may be distilled water, deionized water, or tap water. In someembodiments, the water may contain additives or contaminants. Forinstance, the water may include freshwater or seawater, natural orsynthetic brine, or salt water. In some embodiments, salt or otherorganic compounds may be incorporated into the water to control certainproperties of the water, and thus the drilling fluid, such as density.Without being bound by any particular theory, increasing the saturationof water by increasing the salt concentration or the level of otherorganic compounds in the water may increase the density of the water,and thus, the drilling fluid. Suitable salts may include, but are notlimited to, alkali metal chlorides, hydroxides, or carboxylates. In someembodiments, suitable salts may include sodium, calcium, cesium, zinc,aluminum, magnesium, potassium, strontium, silicon, lithium, chlorides,bromides, carbonates, iodides, chlorates, bromates, formates, nitrates,sulfates, phosphates, oxides, fluorides and combinations of these. Insome particular embodiments, brine may be used in the aqueous phase.Without being bound by any particular theory, brine may be used tocreate osmotic balance between the drilling fluid and the subterraneanformation.

The drilling fluid may contain from 10 wt % to 95 wt % water based onthe total weight of the drilling fluid. In some embodiments, thedrilling fluid may contain from 28 to 850 lb/bbl of water based on thetotal weight of the drilling fluid. The drilling fluid may contain from28 lb/bbl to 810 lb/bbl, from 30 to 800 lb/bbl, from 50 to 800 lb/bbl,from 75 to 800 lb/bbl, or from 100 to 800 lb/bbl of water. In someembodiments, the drilling fluid may contain from 200 to 800, or 300 to600, or 500 to 810 lb/bbl of the oleaginous phase. In some embodiments,the drilling fluid may contain from 28 to 630 lbs/bbl, such as from 30to 600 lbs/bbl, from 50 to 500 lbs/bbl, from 100 to 500 lb/bbl, or 200to 500 lbs/bbl of water.

Without being bound by any particular theory, the water content mayallow the drilling fluid to have proper flowability, ensuring that theclay-based material is not overly viscous, nor overly thin. In someembodiments, the drilling fluid may have about the density of water,which may allow for increased amounts of water in the drilling fluid.Similarly, in some embodiments, the drilling fluid may have a densitythat exceeds 150 pounds per cubic foot (lbs/ft³), allowing minimalamounts of water in the drilling fluid.

In some embodiments, the drilling fluid may also contain at least oneadditive. The one or more additives may be any additives known to besuitable for drilling fluids. As non-limiting examples, suitableadditives may include weighting agents, fluid loss control agents, lostcirculation control agents, other surfactants, antifoaming agents,supplemental emulsifiers, weighting agent, fluid loss additives,viscosity adjusters, an alkali reserve, specialty additives, andcombinations of these.

One or more additives may be incorporated into the drilling fluid toenhance one or more characteristics of the drilling fluid. Aviscosifier, also referred to as a rheology modifier, may be added tothe drilling fluid to impart non-Newtonian fluid rheology to thedrilling fluid to facilitate lifting and conveying rock cuttings to thesurface of the wellbore. Examples of viscosifiers may include, but arenot limited to polyacrylamide, polyanionic cellulose, or combinations ofthese. In some embodiments, the drilling fluid may include xanthan gum,a polysaccharide commonly referred to as XC polymer. The XC polymer maybe added to the water-based drilling fluid to produce a flat velocityprofile of the water-based drilling fluid in annular flow, which mayhelp to improve the efficiency of the drilling fluid, in particularlower density drilling fluids, in lifting and conveying rock cuttings tothe surface.

In some embodiments, the drilling fluid may contain from 0.01 wt % to 20wt % of the one or more additives based on the total weight of thedrilling fluid. The drilling fluid may contain from 0.02 lb/bbl to 180lb/bbl of the one or more additives based on the total weight of thedrilling fluid, such as from 0.02 to 150 lb/bbl, or from 0.05 to 150lb/bbl. In some embodiments, the drilling fluid may contain from 0.1 to150 lb/bbl, or from 0.1 to 100 lb/bbl, or from 1 to 100 lb/bbl of theone or more additives. In some particular embodiments, the drillingfluid may include from 0.025 to 1 lb/bbl of the XC polymer. Inembodiments, the drilling fluid may include from 0.025 to 10 lb/bblstarch.

In some embodiments, the one or more additives may include solids,sometimes referred to as weighting material, which may be dispersed inthe drilling fluid. The solids may be finely divided solids having ahigh specific gravity (SG) that may be added to the drilling fluid toincrease the density of the drilling fluid. Examples of weightingmaterials suitable for use as the solid include, but are not limited to,barite (minimum SG of 4.20 grams per centimeter cubed (g/cm³)), hematite(minimum SG of 5.05 g/cm³), calcium carbonate (minimum SG of 2.7-2.8g/cm³), siderite (minimum SG of 3.8 g/cm³), ilmenite (minimum SG of 4.6g/cm³), other weighting materials, or any combination of these weightingmaterials. In some embodiments, the drilling fluid may include barite asthe solid.

In embodiments, the drilling fluid may have a solids content of from 1wt % to 80 wt % based on the weight of the solid weighing material basedon the total weight of the drilling fluid. The drilling fluid may have asolids content of from 2.5 lb/bbl to 720 lb/bbl, such as from 2.5 to 720lb/bbl, or 2.5 to 700 lb/bbl. In some embodiments, the drilling fluidmay have a solids content of from 5 to 700 lb/bbl, from 50 to 500lb/bbl, or from 100 to 600 lb/bbl.

As stated, the addition of solids may be used to control the density ofthe drilling fluid. In some embodiments, the drilling fluid may have adensity of from 50 pounds of mass per cubic foot (pcf) to 160 pcf, asmeasured using Fann Model 140 Mud Balance according to ASTM StandardD4380. For instance, the drilling fluid may have a density of from 63pcf to 150 pcf, from 50 pcf to 140 pcf, from 55 pcf to 160 pcf, from 60pcf to 150 pcf, from 60 pcf to 140 pcf, from 100 pcf to 160 pcf, from 70pcf to 150 pcf, or from 70 pcf to 100 pcf. The drilling fluid may have adensity that is greater than or equal to 50 pcf, greater than or equalto 70 pcf, or greater than or equal to 100 pcf. In some embodiments, thedrilling fluid may have a density of from 120 pcf to 160 pcf.

Embodiments of the disclosure additionally relate to methods ofproducing an anti-bit balling drilling fluid. The produced drillingfluids may be in accordance with any of the embodiments previouslydescribed. The method may include mixing water, a clay-based component,and at least one of a surfactant having Formula (I) or a polyethyleneglycol having Formula (II), in accordance with any of the embodimentspreviously described.

In some embodiments, the mixture may be mixed at a shear speed of from300 rotations per minute (RPM) to 11500 RPM, such as from 300 RPM to 600RPM, or from 600 RPM to 900 RPM. The mixture may be sheared at 10000 RPMfor from 10 minutes to 100 minutes, such as from 10 minutes to 15minutes, or from 20 minutes to 40 minutes, or from 60 minutes to 80minutes.

Embodiments of the disclosure may also relate to method for using thedrilling fluid in drilling operations. The drilling fluid may be inaccordance with any of the embodiments previously described. In someembodiments, the drilling fluid may be introduced into a subterraneanformation. Introducing may involve injecting the drilling fluid into thesubterranean formation. In some embodiments, the drilling fluid may beinjected through a drill string to a drill bit and recirculating thedrilling fluid. In some embodiments the subterranean formation may be awell. The drilling fluid may at least be partially circulated within thesubterranean formation. Recirculating the fluid may allow the drillingfluid to cool and lubricate the drill bit and to lift rock cuttings awayfrom the drill bit, carrying the cuttings upwards to the surface toclean the wellbore. The drilling fluid may additionally providehydrostatic pressure to support the sidewalls of the wellbore andprevent the sidewalls from collapsing onto the drill string.

As previously described, the drilling fluid of the present embodimentsmay reduce the tendency for bit-balling to occur on a drill bit.Bit-balling refers to the accumulation of cuttings on the drill bit,which slow and even stop the drill bit from properly performing. Thetendency for cuttings to accumulate may be referred to as the accretionpercentage, or the percentage of growth of the cuttings (or othercomponents) to accumulate on the drill bit. In some particularapplications, it may be desirable to maintain an accretion percentage ofless than or equal to 20% to ensure optimal drilling conditions. In someembodiments the drilling fluid of the present embodiments may produce anaccretion percentage of less than or equal to 20%, such as less than orequal to 18%, less than or equal to 16%, such as less than or equal to15%, less than or equal to 14%, less than or equal to 12%, less than orequal to 10%, or less than or equal to 5%.

EXAMPLES

The anti-bit balling drilling fluids of the present disclosure may haveimproved anti-bit balling characteristics over conventional drillingfluids, which may, in some embodiments, be due in part to thesurfactant, the polyethylene glycol, or in some embodiments, both.

Table 1 lists 6 different suitable examples of the polyethylene glycolof the present disclosure, Polyethylene Glycol Examples (PG Ex.) 1 to 6.

TABLE 1 Suitable Polyethylene Glycol Examples Property PG Ex. 1 PG Ex. 2PG Ex. 3 PG Ex. 4 PG Ex. 5 PG Ex. 6 Molecular 200 300 400 600 1200 1500Weight g/mol Appearance Clear Clear Clear Clear Solid Solid at 25° C.Viscous Viscous Viscous Viscous Liquid Liquid Liquid Liquid Hydroxyl535-590 356-394 267-295 178-197 89-99 70.5-83   No. (mgKOH/g) Water %,0.5 0.5 0.5 0.5 0.5 0.5 Max. Color 40 40 40 40 50 50 (APHA) at 25° C.,Max. pH at 25° C. 4.5-7.5 4.5-7.5 4.5-7.5 4.5-7.5 4.5-7.5 4.5-7.5 in Aq.Soln. Density at 1.1238 1.12-1.13 1.1255 1.1258 1.0919 1.0919 25° C.,g/mL Freezing Sets to 5-9 4-8 17-12 42-46 42-46 Range ° C. glass below−65 Flash Point >150 >150 >150 >220 >240 >240 ° C. Ash 0.1 0.1 0.1 0 0.10.1 Content %, Max.

The accretion properties of several samples were tested to comparedrilling fluids of the present embodiments with conventional drillingfluids that did not contain the surfactant or the polyethylene glycol ofthe present disclosure. Four formulations were tested, with twocomparative examples and two examples that were in accordance with theembodiments previously described. The composition of each formulation islisted in Tables 2 to 5. The composition was continuously mixed using aHamilton Beach Model HMD 400 mixer at 11500 RPM shear. The time eachcomponent was added to the mixture is also listed.

TABLE 2 Formulation of Comparative Example 1 - Drilling Fluid WithoutAnti-Bit Balling Additives Component Time Added Amount Water 0 minutes308 cubic centimeters (cc) Deformer 0 minutes 2 drops XC Polymer¹ 15minutes 0.75 grams (g) PAC-R² 15 minutes 2 g Starch 15 minutes 6 g Lime10 minutes 2 g CaCO₃ (fine) 5 minutes 35 g Calibrated Bentonite 5minutes 30 g RevDust³ 5 minutes 5 g ¹Xanthan gum polymer, commerciallyavailable from M-I Swaco (Houston, TX) ²Polyanionic cellulose,commercially available from M-I Swaco (Houston, TX) ³Ground calciummontmorillonite clay, commercially available from Milwhite, Inc.(Brownsville, TX)

TABLE 3 Formulation of Comparative Example 2 - Drilling Fluid WithConventional Anti-Bit-Balling Additive Component Time Added Amount Water0 minutes 308 cc Deformer 0 minutes 2 drops XC Polymer¹ 15 minutes 0.75g PAC-R² 15 minutes 2 g Starch 15 minutes 6 g Commercial lubricant⁴ 10minutes 1 g Lime 10 minutes 2 g CaCO₃ (fine) 5 minutes 35 g CalibratedBentonite 5 minutes 30 g RevDust³ 5 minutes 5 g ¹Xanthan gum polymer,commercially available from M-I Swaco (Houston, TX) ²Polyanioniccellulose, commercially available from M-I Swaco (Houston, TX) ³Groundcalcium montmorillonite clay, commercially available from Milwhite, Inc.(Brownsville, TX) ⁴LUBE 167, commercially available from M-I Swaco(Houston, TX)

TABLE 4 Formulation of Example 1 - Drilling Fluid With PolyethyleneGlycol as Anti-Bit Balling Additive Component Time Added Amount Water 0minutes 308 cc Deformer 0 minutes 2 drops XC Polymer¹ 15 minutes 0.75 gPAC-R² 15 minutes 2 g Starch 15 minutes 6 g Polyethylene glycol 10minutes 1 g Lime 10 minutes 2 g CaCO₃ (fine) 5 minutes 35 g CalibratedBentonite 5 minutes 30 g RevDust³ 5 minutes 5 g ¹Xanthan gum polymer,commercially available from M-I Swaco (Houston, TX) ²Polyanioniccellulose, commercially available from M-I Swaco (Houston, TX) ³Groundcalcium montmorillonite clay, commercially available from Milwhite, Inc.(Brownsville, TX)

TABLE 5 Formulation of Example 2 - Drilling Fluid With Surfactant asAnti-Bit Balling Additive Component Time Added Amount Water 0 minutes308 cc Deformer 0 minutes 2 drops XC Polymer¹ 15 minutes 0.75 g PAC-R²15 minutes 2 g Starch 15 minutes 6 g Ethylene oxide condensate of 10minutes 1 g synthetic branched ethoxylates Lime 10 minutes 2 g CaCO₃(fine) 5 minutes 35 g Calibrated Bentonite 5 minutes 30 g RevDust³ 5minutes 5 g ¹Xanthan gum polymer, commercially available from M-I Swaco(Houston, TX) ²Polyanionic cellulose, commercially available from M-ISwaco (Houston, TX) ³Ground calcium montmorillonite clay, commerciallyavailable from Milwhite, Inc. (Brownsville, TX)

For each of the four formulations, the drilling fluid was prepared and apre-weighed Monel® nickel alloy accretion tube was added to theformulation. The drilling fluid and accretion tube were hot rolled at150° F. for 4 hours. The drilling fluid was allowed to cool to roomtemperature (about 72° F.) and was stirred for 30 seconds on a HamiltonBeach HMD 400 multi-mixer at low shear between 1000 RPM and 1200 RPM.The accretion tube was set on a screen and the mud was allowed to drainfrom the tube for 10 seconds, upon which the tube was again weighed. Theweight of the mud remaining on the tube was determined by subtractingthe final weight after 10 seconds of mud run-off from the initial weightof the dry tube. The accretion results are listed in Table 6.

TABLE 6 Accretion Results Difference Weight of in weight Weight of dryAccretion tube (Mud accretion tube after hot rolling remaining AccretionFormulation (Initial Weight) (Final Weight) on tube) PercentageComparative 120.68 g 141.81 g 21.13 g 17.51% Example 1 Comparative120.47 g 138.85 g 18.38 g 15.26% Example 2 Example 1 120.61 g 138.75 g18.14 g 15.04% Example 2 120.57 g 138.22 g 17.72 g 14.64%

To further demonstrate the results of the accretion tests, photographswere taken of both the dry accretion tube and the accretion tube after10 seconds, as previously described.

FIG. 1A is a photograph of the accretion tube results of ComparativeExample 1. Comparative Example 1 was a drilling fluid without ananti-bit balling additive. The dry accretion tube had a starting dryweight of 120.68 g, shown on the left in FIG. 1A. Comparative Example 1was hot rolled in the tube for 4 hours, placed on a screen, and the mudwas allowed to drain for 10 seconds. After 10 seconds, the photograph onthe right was taken and the accretion tube was weighed at 141.81 g. Asshown in FIG. 1A, the drilling fluid is clinging to the accretion tubeand even pooling at the bottom of the screen. Over 20 g of mud remainedon the accretion tube.

FIG. 1B is a photograph of the accretion tube results of ComparativeExample 2.

Comparative Example 2 was a drilling fluid containing a conventionalanti-bit balling additive, Lube-167, a water-based lubricantcommercially available from M-I Swaco (Houston, Tex.). The dry accretiontube had a starting dry weight of 120.47 g, shown on the left in FIG.1B. Comparative Example 2 was hot rolled in the tube for 4 hours, placedon a screen, and the mud was allowed to drain for 10 seconds. After 10seconds, the photograph on the right was taken and the accretion tubewas weighed at 138.85 g. As shown in FIG. 1B, the drilling fluid ofComparative Example 2 is covering the accretion tube and again ispooling at the bottom of the screen. About 18.4 g of mud remained on theaccretion tube.

FIG. 2A is a photograph of the accretion tube results of Example 1 ofthe present disclosure. Example 1 was a drilling fluid utilizing apolyethylene glycol of the present disclosure as an anti-bit ballingadditive. The dry accretion tube had a starting dry weight of 120.61 g,shown on the left of FIG. 2A. Example 1 was hot rolled in the tube for 4hours, placed on a screen, and the mud was allowed to drain for 10seconds. After 10 seconds, the photograph on the right was taken and theaccretion tube was weighed at 138.75 g. As shown in FIG. 2A, thedrilling fluid of Example 1 is not clinging to the groves in theaccretion tube and does not pool at the bottom of the screen. About 18.2g of mud remained on the accretion tube.

Finally, FIG. 2B is a photograph of the accretion tube results ofExample 2 of the present disclosure. Example 2 was a drilling fluidutilizing a surfactant of the present disclosure as an anti-bit ballingadditive. The dry accretion tube had a starting dry weight of 120.57 g,shown on the left in FIG. 2B. Example 2 was hot rolled in the tube for 4hours, placed on a screen, and the mud was allowed to drain for 10seconds. After 10 seconds, the photograph on the right was taken and theaccretion tube was weighed at 138.22 g. As shown in FIG. 2B, thedrilling fluid of Example 2 is not clinging to the accretion tube anddoes not pool at the bottom of the screen, and enough drilling fluid hasbeen drained from the tube such that portions of the tube are againvisible. Only about 17.2 g of mud remained on the accretion tube afterthe 10 second drain.

A first aspect of the disclosure is directed to an anti-bit ballingfluid comprising at least one of a surfactant comprising the formula:R—(OC₂H₄)_(x)—OH, where R is a hydrocarbyl group having from 10 to 20carbon atoms, x is an integer from 1 and 10, or a polyethylene glycolcomprising Formula (II):

where n is an integer from 1 to 50.

A second aspect of the disclosure includes the first aspect, where thesurfactant has a hydrophilic-lipophilic balance (HLB) of from 8 to 16.

A third aspect of the disclosure includes the first or second aspects,where R comprises 13 carbon atoms.

A fourth aspect of the disclosure includes any of the first throughthird aspects, where the drilling fluid comprises from 28 to 810 lb/bblof the oleaginous phase based on the total weight of the drilling fluid.

A fifth aspect of the disclosure includes any of the first throughfourth aspects, where R is an isotridecyl (C₁₃H₂₇) group.

A sixth aspect of the disclosure includes any of the first through fifthaspects, where x is from 5 to 10.

A seventh aspect of the disclosure includes any of the first throughsixth aspects, where x is from 7 to 9.

An eighth aspect of the disclosure includes any of the first throughseventh aspects, where the surfactant has an HLB of from 13 to 15.

A ninth aspect of the disclosure includes any of the first througheighth aspects, where the surfactant is a naturally-derived fattyalcohol.

A tenth aspect of the disclosure includes any of the first through ninthaspects, where the surfactant is a synthetically-derived fatty alcohol.

An eleventh aspect of the disclosure includes any of the first throughtenth aspects, where the surfactant comprises ethylene oxide condensateof branched isotridecyl alcohol.

A twelfth aspect of the disclosure includes any of the first througheleventh aspects, where the polyethylene glycol has a weight averagemolecular weight of from 300 grams per mol (g/mol) to 500 g/mol, asmeasured according to gel permeation chromatography (GPC).

A thirteenth aspect of the disclosure includes any of the first throughtwelfth aspects, where the anti-bit balling fluid comprises from 0.02 to180 pounds per barrel (lb/bbl) of the surfactant based on the totalweight of the anti-bit balling fluid.

A fourteenth aspect of the disclosure includes any of the first throughthirteenth aspects, where the anti-bit balling fluid comprises from 0.02to 180 lb/bbl of the polyethylene glycol based on the total weight ofthe anti-bit balling fluid.

A fifteenth aspect of the disclosure is directed to a drilling fluidcomprising: water; a clay-based component; and at least one of asurfactant comprising the formula: R—(OC₂H₄)_(x)—OH, where R is ahydrocarbyl group having from 10 to 20 carbon atoms, x is an integerfrom 1 and 10, or a polyethylene glycol comprising Formula (II):

where n is an integer from 1 to 50.

A sixteenth aspect of the disclosure includes the fifteenth aspect,where the surfactant has an HLB of from 8 to 16.

A seventeenth aspect of the disclosure includes any of the fifteenththrough sixteenth aspects, where R is: an alkyl group comprising 12 to15 carbons; or an alkenyl group comprising from 12 to 15 carbon atoms.

An eighteenth aspect of the disclosure includes any of the fifteenththrough seventeenth aspects, where R comprises 13 carbon atoms.

A nineteenth aspect of the disclosure includes any of the fifteenththrough eighteenth aspects, where R comprises an isotridecyl (C₁₃H₂₇)group.

A twentieth aspect of the disclosure includes any of the fifteenththrough nineteenth aspects, where x is from 5 to 10.

A twenty-first aspect of the disclosure includes any of the fifteenththrough twentieth aspects, where x is from 7 to 9.

A twenty-second aspect of the disclosure includes any of the fifteenththrough twenty-first aspects, where the surfactant has an HLB of from 13to 15.

A twenty-third aspect of the disclosure includes any of the fifteenththrough twenty-second aspects, where the surfactant is anaturally-derived fatty alcohol.

A twenty-fourth aspect of the disclosure includes any of the fifteenththrough twenty-second aspects, where the surfactant is asynthetically-derived fatty alcohol.

A twenty-fifth aspect of the disclosure includes any of the fifteenththrough twenty-fourth aspects, where the surfactant comprises ethyleneoxide condensate of branched isotridecyl alcohol.

A twenty-sixth aspect of the disclosure includes any of the firstthrough twenty-fifth aspects, where the polyethylene glycol has a weightaverage molecular weight of from 300 grams per mol (g/mol) to 500 g/mol,as measured according to GPC.

A twenty-seventh aspect of the disclosure includes any of the firstthrough twenty-sixth aspects, where the drilling fluid comprises from 28to 850 lb/bbl water based on the total weight of the drilling fluid.

A twenty-eighth aspect of the disclosure includes any of the firstthrough twenty-seventh aspects, where the drilling fluid comprises from28 to 720 lb/bbl of the clay-based component based on the total weightof the drilling fluid.

A twenty-ninth aspect of the disclosure includes any of the firstthrough twenty-eighth aspects, where the drilling fluid comprises from0.02 to 180 lb/bbl of the surfactant, the polyethylene glycol, or both,based on the total weight of the drilling fluid.

A thirtieth aspect of the disclosure includes any of the first throughtwenty-ninth aspects, where the clay-based component comprises one ormore components selected from the group consisting of lime (CaO), CaCO₃,bentonite, montmorillonite clay, barium sulfate (barite), hematite(Fe₂O₃), mullite (3Al₂O₃.2SiO₂ or 2Al₂O₃ SiO₂), kaolin, (Al₂Si₂O₅(OH)₄or kaolinite), alumina (Al₂O₃, or aluminum oxide), silicon carbide,tungsten carbide, and combinations thereof.

A thirty-first aspect of the disclosure includes any of the firstthrough thirtieth aspects, further comprising at least one or moreadditives selected from the group consisting of weighting agents, fluidloss control agents, lost circulation control agents, viscosifiers,dispersants, pH buffers, electrolytes, glycols, glycerols, dispersionaids, corrosion inhibitors, defoamers, deformers, starches, xanthan gumpolymers, other specialty additives, and combinations thereof.

A thirty-second aspect of the disclosure includes any of the fifteenththrough thirty-first aspects, where the drilling fluid has an accretionpercentage of less than or equal to 18%.

A thirty-third aspect of the disclosure is directed to a method ofproducing a drilling fluid, the method comprising: mixing water, aclay-based component, and at least one of a surfactant comprising theformula: R—(OC₂H₄)_(x)—OH, where R is a hydrocarbyl group having from 10to 20 carbon atoms, x is an integer from 1 and 10, or a polyethyleneglycol comprising Formula (II):

where n is an integer from 1 to 50, to produce the drilling fluid.

A thirty-fourth aspect of the disclosure is directed to a method forusing a drilling fluid in drilling operations, the method comprising:mixing water, a clay-based component, and at least one of a surfactantcomprising the formula: R—(OC₂H₄)_(x)—OH, where R is a hydrocarbyl grouphaving from 10 to 20 carbon atoms, x is an integer from 1 and 10, or apolyethylene glycol comprising Formula (II):

where n is an integer from 1 to 50, to produce the drilling fluid, andintroducing the drilling fluid to a subterranean formation.

A thirty-fifth aspect of the disclosure includes the thirty-fourthaspect, where the subterranean formation is a well.

A thirty-sixth aspect of the disclosure includes any of thethirty-fourth through thirty-fifth aspects, where introducing thedrilling fluid comprises injecting the drilling fluid and at leastpartially circulating the drilling fluid within the subterraneanformation.

A thirty-seventh aspect of the disclosure includes any of thethirty-third through thirty-sixth aspects, where the surfactant has anHLB of from 8 to 16.

A thirty-eighth aspect of the disclosure includes any of thethirty-third through thirty-seventh aspects, where R is: an alkyl groupcomprising 12 to 15 carbons; or an alkenyl group comprising from 12 to15 carbon atoms.

A thirty-ninth aspect of the disclosure includes any of the thirty-thirdthrough thirty-eighth aspects, where R has 13 carbon atoms.

A fortieth aspect of the disclosure includes any of the thirty-thirdthrough thirty-ninth aspects, where R is an isotridecyl (C₁₃H₂₇) group.

A forty-first aspect of the disclosure includes any of the thirty-thirdthrough fortieth aspects, where x is from 5 to 10.

A forty-second aspect of the disclosure includes any of the thirty-thirdthrough forty-first aspects, where x is from 7 to 9.

A forty-third aspect of the disclosure includes any of the thirty-thirdthrough forty-second aspects, where the surfactant has an HLB of from 13to 15.

A forty-fourth aspect of the disclosure includes any of the thirty-thirdthrough forty-third aspects, where the surfactant is a naturally-derivedfatty alcohol.

A forty-fifth aspect of the disclosure includes any of the thirty-thirdthrough forty-fourth aspects, where the surfactant is asynthetically-derived fatty alcohol.

A forty-sixth aspect of the disclosure includes any of the thirty-thirdthrough forty-fourth aspects, where the surfactant comprises ethyleneoxide condensate of branched isotridecyl alcohol.

A forty-seventh aspect of the disclosure includes any of thethirty-third through forty-sixth aspects, where the polyethylene glycolhas a weight average molecular weight of from 300 grams per mol (g/mol)to 500 g/mol, as measured according to GPC.

A forty-eighth aspect of the disclosure includes any of the thirty-thirdthrough forty-seventh aspects, where the drilling fluid comprises from28 to 850 lb/bbl water based on the total weight of the drilling fluid.

A forty-ninth aspect of the disclosure includes any of the thirty-thirdthrough forty-eighth aspects, where the drilling fluid comprises from 28to 720 lb/bbl of the clay-based component based on the total weight ofthe drilling fluid.

A fiftieth aspect of the disclosure includes any of the thirty-thirdthrough forty-ninth aspects, where the drilling fluid comprises from0.02 to 180 lb/bbl of the surfactant, the polyethylene glycol, or both,based on the total weight of the drilling fluid.

A fifty-first aspect of the disclosure includes any of the thirty-thirdthrough fiftieth aspects, where the clay-based component comprises oneor more components selected from the group consisting of lime (CaO),CaCO₃, bentonite, montmorillonite clay, barium sulfate (barite),hematite (Fe₂O₃), mullite (3Al₂O₃.2SiO₂ or 2Al₂O₃.SiO₂), kaolin,(Al₂Si₂O₅(OH)₄ or kaolinite), alumina (Al₂O₃, or aluminum oxide),silicon carbide, tungsten carbide, and combinations thereof.

A fifty-second aspect of the disclosure includes any of the thirty-thirdthrough fifty-first aspects, further comprising at least one or moreadditives selected from the group consisting of weighting agents, fluidloss control agents, lost circulation control agents, viscosifiers,dispersants, pH buffers, electrolytes, glycols, glycerols, dispersionaids, corrosion inhibitors, defoamers, deformers, starches, xanthan gumpolymers, other specialty additives, and combinations thereof.

A fifty-third aspect of the disclosure includes any of the thirty-thirdthrough fifty-second aspects, where the drilling fluid has an accretionpercentage of less than or equal to 18%.

The following description of the embodiments is exemplary andillustrative in nature and is in no way intended to be limiting it itsapplication or use. As used throughout this disclosure, the singularforms “a,” “an” and “the” include plural referents unless the contextclearly dictates otherwise. Thus, for example, reference to “a”component includes aspects having two or more such components, unlessthe context clearly indicates otherwise.

It should be apparent to those skilled in the art that variousmodifications and variations may be made to the embodiments describedwithin without departing from the spirit and scope of the claimedsubject matter. Thus, it is intended that the specification cover themodifications and variations of the various embodiments described withinprovided such modification and variations come within the scope of theappended claims and their equivalents.

It is noted that one or more of the following claims utilize the term“where” as a transitional phrase. For the purposes of defining thepresent technology, it is noted that this term is introduced in theclaims as an open-ended transitional phrase that is used to introduce arecitation of a series of characteristics of the structure and should beinterpreted in like manner as the more commonly used open-ended preambleterm “comprising.”

Having described the subject matter of the present disclosure in detailand by reference to specific embodiments of any of these, it is notedthat the various details disclosed within should not be taken to implythat these details relate to elements that are essential components ofthe various embodiments described within, even in cases where aparticular element is illustrated in each of the drawings that accompanythe present description. Further, it should be apparent thatmodifications and variations are possible without departing from thescope of the present disclosure, including, but not limited to,embodiments defined in the appended claims. More specifically, althoughsome aspects of the present disclosure are identified as particularlyadvantageous, it is contemplated that the present disclosure is notnecessarily limited to these aspects.

1. A drilling fluid comprising: water; a clay-based component; and apolyethylene glycol comprising Formula (I):

where n is an integer from 1 to
 50. 2. The drilling fluid of claim 1,where the polyethylene glycol has a weight average molecular weight offrom 300 grams per mol (g/mol) to 500 g/mol, as measured according toGPC.
 3. The drilling fluid of claim 1, where the drilling fluidcomprises from 28 to 850 lb/bbl water based on total weight of thedrilling fluid.
 4. The drilling fluid of claim 1, where the drillingfluid comprises from 28 to 720 lb/bbl of the clay-based component basedon total weight of the drilling fluid.
 5. The drilling fluid of claim 1,where the drilling fluid comprises from 0.02 to 180 lb/bbl of thepolyethylene glycol, based on total weight of the drilling fluid.
 6. Thedrilling fluid of claim 1, where the clay-based component comprises oneor more components selected from the group consisting of lime (CaO),CaCO₃, bentonite, montmorillonite clay, barium sulfate (barite),hematite (Fe₂O₃), mullite (3Al₂O₃.2SiO₂ or 2Al₂O₃.SiO₂), kaolin,(Al₂Si₂O₅(OH)₄ or kaolinite), alumina (Al₂O₃, or aluminum oxide),silicon carbide, tungsten carbide, and combinations thereof.
 7. Thedrilling fluid of claim 1, further comprising at least one or moreadditives selected from the group consisting of weighting agents, fluidloss control agents, lost circulation control agents, viscosifiers,dispersants, pH buffers, electrolytes, glycols, glycerols, dispersionaids, corrosion inhibitors, defoamers, deformers, starches, xanthan gumpolymers, other specialty additives, and combinations thereof.
 8. Thedrilling fluid of claim 1, where the drilling fluid has an accretionpercentage of less than or equal to 18%.